<!doctype html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>Document</title>
	<style type="text/css">
	*{ box-sizing:border-box; }
	#box{ margin:50px;
		 width:200px;
		 height:100px;
		 background: red;
		 animation:aa 5s;}
	@keyframes aa{
		0%{background: red; }
		25%{background: yellow;}
		50%{background: pink;
		75%{background: blue;}
		100%{background: black;}  
	 }

	</style>
</head>
<body>
	<div id="box">		
	</div>
</body>
</html>
